I recently replaced the rubber washers on an old shower valve with
I also had to replace the seat since it had chewed up one washer.
The rubber washers on the unit were FLAT BLACK RUBBER - 3/8L.
I used DOME SHAPED black rubber washers.
They fit and work fine.
I don't see any difference in operation.
Anyone know any reasons why they - FLAT + DOMED - can't be used interchangeably
I have always used whatever worked.